The Forgotten Creatures Who Ruled Before the “Great Death”

Researchers have uncovered in "Southern Pangaea" (now the southern part of Africa) fossils of creatures that lived shortly before the event known as the "Great Dying," which wiped out about 70% of terrestrial species and an even larger proportion of marine species.

Uncovering the Perm's past in Africa

For more than 15 years, international researchers have been excavating and analyzing fossils in Africa to better understand the Permian Period—a geological period that lasted from 299 to 252 million years ago and ended with the most severe mass extinction event in Earth’s history. The study, led by researchers from the University of Washington and the Field Museum of Natural History, focuses on identifying the creatures that lived in southern Pangaea (Earth’s only supercontinent at the time) shortly before the event known as the “Great Dying,” which wiped out about 70 percent of terrestrial species and an even larger proportion of marine species.

“This mass extinction was a real catastrophe for life on Earth and changed the course of evolution,” said Christian Sidor, professor of biology and curator of vertebrate paleontology at the UW Burke Museum. “But we lack a comprehensive picture of who survived, who didn’t—and why. The fossils we collected in Tanzania and Zambia will provide a more global perspective on this unprecedented period in our planet’s natural history.”

Sidor, along with Kenneth Engelchik, curator of paleomammal at the Field Museum, edited a 14-part series of articles that was published on August 7 in the journal Journal of Vertebrate Paleontology The series presents recent findings on the wide variety of animals that inhabited Africa during the Permian period—from saber-toothed carnivores to burrowing herbivores to large amphibians resembling salamanders.

Fossil treasures across South Africa (geographically)

All of these finds were recovered from three basins in southern Africa (the geographic region): the Ruhoho Basin in southern Tanzania, the Luangwa Basin in eastern Zambia, and the Middle Zambezi Basin in southern Zambia. Most were discovered by team members during month-long excavation trips in the region over the past 17 years; others were analyzed from museum collections of specimens excavated decades ago.

“These areas in Zambia and Tanzania have preserved spectacular fossils from the Permian period,” Sidor said. “They give us an unprecedented glimpse into life on land in the run-up to the mass extinction.”

Since 2007, Siddur and his team—including UW undergraduate and graduate students—have embarked on five research expeditions to the Ruhoho Basin and four to the Middle Zambezi and Luangwa Basins, in partnership with authorities in Tanzania and Zambia. The researchers have walked between field sites miles apart to collect fossils, staying in villages or camping in the field. All fossils collected will be returned to Tanzania and Zambia after the research is complete.

Life before the “Great Death”"

The Permian marks the end of the Paleozoic Era. During this period, animals—which had originally evolved in bodies of water—began to colonize land, and complex terrestrial ecosystems emerged. During the Permian, a wide variety of amphibians and reptile-like creatures roamed a variety of habitats—from early forests to arid valleys. The end-Permian mass extinction—the exact cause of which is still debated—wiped out many of these systems and ushered in the Mesozoic Era, in which dinosaurs evolved and the first birds, flowering plants, and mammals also appeared.

For decades, scientific knowledge of the Permian, the “Big Die-Off” and the early Mesozoic was based mainly on the Kru Basin in South Africa, which preserves a nearly complete fossil record from before and after the extinction. However, since the 30s, it has been clear that basins in Tanzania and Zambia contain a nearly complete fossil record for this time period. The expeditions by Sidor, Engelchik and their colleagues are the most comprehensive analysis to date of the regional fossil record from before and after the “Big Die-Off”. In 2018, the researchers published a comprehensive analysis of the post-Permian fauna in the Ruhoho and Luangwa basins; the new papers include an analysis of geological evidence from the earlier Permian.

Fine fossils for global comparisons

“The number of specimens we found in Zambia and Tanzania is so large, and their state of preservation is so good, that we can make comparisons at the species level with what is found in South Africa,” Sidor said. “There is no better place, as far as I know, to get sufficient detail from this period to draw accurate conclusions and comparisons.”

The team's papers describe several new species of dicynodonts—small, burrowing, reptile-like herbivores that first evolved in the mid-Permian. Until the mass extinction, dicynodonts—many of which had beak-like snouts and two small tusks that probably aided in digging—were the dominant herbivores on land. The findings also include several new species of gorgonopsians—large, saber-toothed carnivores—and a new species of temnospondyl, a large salamander-like amphibian.

“Now we can compare two different geographic regions of Pangaea and see what happened before and after the end-Permian mass extinction,” Sidor said. “That way we can really start asking who survived and who didn’t.”

for the scientific article DOI: 10.1080 / 02724634.2024.2446616